User Data registration via UI doesn't honour the domain field

##### ISSUE TYPE

* Bug Report

##### COMPONENT NAME

~~~
User Data
~~~

##### CLOUDSTACK VERSION

4.19 (would be present from 4.18 - when managed user data service support was added)
~~~

~~~

##### CONFIGURATION

##### OS / ENVIRONMENT

##### SUMMARY

Registration of user data in a specific domain i.e., by passing the domain in the UI , doesn't honour the domain id passed, rather creates the user data in the domain you are currently logged in to.

##### STEPS TO REPRODUCE

~~~
1. Log in as Admin
2. Create a domain - domain1 under ROOT domain
3. As Admin in the ROOT domain context, register a user data and pass domain as /domain1
4. User data is registered but the domain appears as ROOT and not /domain1
~~~

##### EXPECTED RESULTS

~~~
User data be registered in the correct domain
~~~

##### ACTUAL RESULTS

~~~
User data created / registered in the domain in the current context
~~~

Inizia riproducendo il flusso di registrazione di User Data nella UI: crea domain1 sotto ROOT, quindi registra User Data dal contesto ROOT passando /domain1. Traccia il punto di ingresso della registrazione nella UI e la gestione del campo del dominio. Il lavoro è completato quando User Data viene creato in domain1 anziché nel dominio ROOT corrente.

Scritto dal modello di indicizzazione a partire dal testo della issue.